An account of some cases of the production of colours, not hitherto described

Abstract

Abstract In a former paper Dr. Young, treating of certain phaenomena of coloured light, mentioned a law, according to which it appears, that whenever two portions of the same light arrive at the eye by different routes, either exactly or very nearly in the same direction, the light becomes most intense when the difference of the routes is any multiple of a certain length, and least intense in the intermediate state of the interfering portions, and that this length is different for light of different colours. In the same paper he showed the sufficiency of this law for explaining all the phænomena in the second and third books of Newton's Optics' and in the present communication he illustrates it still further, by applying it to some new distinct cases relating to the colours of fibres, and to the colours of mixed plates.